Meg Ryan is on an apartment search again, with her rocker boyfriend John Mellencamp. But Ryan, who as we previously reported has rented at 40 Mercer St., is now looking to buy.

The actress recently toured a condo at TriBeCa’s 51 Walker St. that was once rented by Leonardo DiCaprio. The 3,200-square-foot, three-bedroom, 3 1/2-bathroom triplex is listed for $5.25 million and comes with a private garden that has a swimming pool and Jacuzzi.

Prudential Douglas Elliman’s Frederik Eklund, a star of Bravo’s “Million Dollar Listing New York,” and John Gomes are the brokers for the apartment, which Gwen Stefani also once called home.

Ryan and Mellencamp also visited the Marble House triplex unit at TriBeCa’s 60 Collister St. The 9,200-square-unit, six-bedroom, five-plus-bathroom condo is listed for $19.99 million and offers “townhouse-style living” with a doorman and parking. The owner of the unit, also listed by Eklund and Gomes, is movie producer Stuart Parr (“8 Mile”). Parr also owns Chelsea’s Stuart Parr Gallery.

Co-op ‘sheiks down’ Vegas mogul Wynn

Sheik Hamad bin Jassim bin Jabr Al-Thani of Qatar, whose $31.5 million bid to buy Huguette Clark’s former Fifth Avenue apartments was rejected, isn’t the only big shot being denied by New York’s snooty co-op boards. Casino boss Steve Wynn was diplomatically discouraged from pursuing the $36 million purchase of a trophy penthouse duplex on East 70th Street that once belonged to late billionaire Teddy Forstmann.

Wynn has recently beefed up his security with ex-Navy SEALs after a business breakup with billionaire Kazuo Okada. Wynn also looked at the city’s priciest co-op, a $65 million home owned by society songbird Denise Rich. He also checked out the $77.5 million Ritz-Carlton penthouse condo owned by real estate developer Christopher Jeffries of Millennium Partners.

Room and boards

Olympic gold medalist Shaun White is looking for an apartment big enough for him and his snowboards and skateboards. He recently toured a $5.75 million condo at TriBeCa’s 72 Reade St. The 3,360-square-foot, three-bedroom, 2 1/2-bathroom full-floor loft has keyed elevator access, original columns, a gas fireplace and a terrace. Listing broker Michael Gravesof Core declined to comment.

We hear . . .

That Corcoran Group broker Karen Kelley and Dick Cavett co-hosted a party for “Extreme Trust: Honesty as Competitive Advantage,” written by Cavett’s wife, Martha Rogers, and Don Peppers. The event at 627 West End Ave., a 6,000-square-foot townhouse listed for $7.495 million by Kelley, was attended by Bill and Judith Davidson Moyers . . . That brokers are already trying to find homes that could work for Pippa Middleton after reports surfaced that she wants to move to NYC

Madge’s Hamptons ‘out house’

Could Madonna be homeless in the Hamptons for the summer?

The Material Mom must vacate her Water Mill mansion on Blank Lane when her lease ends May 15. She’s signed a lease to move back in on Sept. 15. Madonna still owns Kelly Klein’s old Bridgehampton horse farm, but she is not allowed to build a residence on the vast property.

Sighting

Jude Law at the Brewster Carriage House at 374 Broome St., where he was filming Steven Soderbergh’s “psycho-pharmacological” thriller “The Bitter Pill” in a $3.995 million, 2,172-square-foot condo listed by Prudential Douglas Elliman’s Fredrik Eklund and John Gomes.

Lively and let live

After months of looking for digs in the city, Blake Lively and Ryan Reynolds have opted to buy a $2.3 million mansion in Westchester’s tony Bedford area. The house sits on 2 acres and overlooks the Cross River Reservoir.

We hear the couple, who met on the set of “Green Lantern” last year, were “over the top” in their demands for confidentiality with their purchase. And Reynolds, who divorced Scarlett Johansson in 2010, hasn’t been making friends with the locals. When another couple happened to walk out of Richard Gere’s Bedford Post Inn restaurant at the same time, Reynolds became hostile. “Are you following me?” he snarled at the diners, who thought the actor needed a reality check.